PPBP and gastric cancer: In this stage, chemokines/interleukins with low or high expression in precancerous stage appeared “reverse expression.” For example, the chemokines XCL2, XCL1, CXCL7, CXCL4, CXCR5, CXCR3, CXCR2, CXCL2, CXCL13, CXCL11, CX3CL1, CCR9, CCR1, CCL8, CCL5, CCL4, CCL3, CCL25, CCL23, CCL14, and CCL13 were lowly expressed in precancerous stage, while in gastric cancer especially the early and middle stages, the expression trend of these lowly expressed chemokines reversed.